KNX · Room Controllers · ETS6 · HVAC · 9 min read

KNX Room Controllers: Gira, MDT and Zennio Display Configuration

A KNX room controller is a per-room touchscreen device mounted on the wall that shows temperature, setpoint adjustment, HVAC mode, lighting scenes and sometimes presence control. Unlike a central visualisation server, one room controller serves one room. Configuration is entirely in ETS6 — no separate app required.

Room controller vs room thermostat — the key distinction

These two device categories are frequently listed under the same heading in specifications, but they serve different functions and require different ETS6 configurations. Specifying the wrong type leads to either over-complication or missing user control features.

Feature	Room Controller (Touch)	Room Thermostat (Non-touch)
Display type	Colour touchscreen	Small LCD or no display
User interaction	Scene selection, mode change, setpoint, lighting control	Setpoint +/- via push buttons only
HVAC functions	Display + control (or pass setpoint to HVAC controller)	Internal PI control loop sends valve position to KNX
Scene programming	Yes — scene buttons on display	No
Lighting control	Yes — dimmer slider and on/off on display	No
Bus-powered	Yes (most models — Gira 2096, MDT BE-GT55)	Yes (typical)
External 24V needed	No for most models	No
Internal PI control	Optional — some have it, some pass setpoint to separate controller	Yes — PI control inside the device
Example products	Gira 2096 Touch, MDT BE-GT55, Jung F50 EUI	Thermokon SR-MDS, Siemens QAX34.1, MDT SCN-RT1
Typical cost	€300–700	€80–200

In most residential projects, the room controller handles display and setpoint input, while a separate KNX HVAC controller (MDT climate module, Zennio Z41 HVAC, or room thermostat with PI control) performs the actual temperature regulation and sends valve position to the actuator. The room controller sends its setpoint change to the HVAC controller via a group address — not directly to the valve.

Gira 2096 Touch room controller

The Gira 2096-xx-xx series (3.1-inch colour touch display, KNX TP bus-powered) is the most widely specified room controller in European residential KNX projects. It requires no separate 24V supply — the KNX TP bus provides all power. Configuration is entirely in ETS6 using the official Gira product database application.

Hardware specification

• Display: 3.1-inch IPS colour, 240×320px
• Touch: capacitive, 2-point multitouch
• Bus: KNX TP — bus-powered, no external supply
• Temperature sensor: internal NTC (±0.5°C accuracy)
• Backlight: auto-off configurable (30s–5 min)
• Protection: IP20 for indoor wall installation
• Frame options: Gira E2, Gira System 55, Gira Esprit in multiple colours

ETS6 display page configuration

• Up to 4 configurable display pages — swipe between pages
• Page 1 (HVAC): actual temp, setpoint, mode selector, heating/cooling status
• Page 2 (Lighting): up to 4 independent channel dimmer sliders
• Page 3 (Scenes): up to 4 scene buttons with custom labels
• Page 4 (Status): binary status display for up to 4 group addresses
• Optional: door bell page with 2N/DoorBird camera preview via IP

Gira 2096 — HVAC page ETS6 group address assignment

HVAC display page — required group addresses:

  Actual temperature (read):
    GA e.g. 5/1/1 — DPT 9.001 (2-byte float, °C)
    Source: room temperature sensor or thermostat feedback

  Setpoint (send + read):
    GA e.g. 5/1/2 — DPT 9.001 (2-byte float, °C)
    2096 sends new setpoint when user adjusts +/-
    Read: 2096 displays current setpoint from HVAC controller

  HVAC operating mode (send + read):
    GA e.g. 5/1/3 — DPT 20.102 (1-byte HVAC mode)
    Values: 0=Auto, 1=Comfort, 2=Standby, 3=Night, 4=Frost

  Heating/cooling status (read):
    GA e.g. 5/1/4 — DPT 1.001 (1-bit: 0=cooling, 1=heating)
    Displays heating or cooling icon on screen

ETS6 parameter: "Setpoint step" — typically 0.5°C per button press
ETS6 parameter: "Setpoint limits" — min 16°C, max 28°C (configurable)

Keypad lock and protection

• ETS6 parameter: "Keypad lock via KNX" — DPT 1.001 write to group address locks touch input
• PIN lock: 4-digit code configurable in ETS6 — prevents unauthorised setpoint changes
• Hotel mode: lock display after timeout and restore to default setpoint — useful for guest rooms
• Cleaning mode: tap-lock the display during cleaning without entering PIN

MDT BE-GT55 Touch room controller

The MDT BE-GT55 is a 5.5-inch KNX bus-powered room controller with higher resolution and a larger display than the Gira 2096. It is configured via the MDT Parametrizer tool combined with ETS6 import — a two-tool workflow similar to Gira GPA.

Hardware specification

• Display: 5.5-inch IPS colour, 720×1280px
• Touch: projected capacitive
• Bus: KNX TP bus-powered (no external supply)
• Internal temperature sensor: NTC, ±0.5°C
• Proximity sensor: wakes display on approach
• Flush mount: 55×55mm cutout (Gira System 55 compatible frame)

HVAC features vs Gira 2096

• Shows floor heating zone status alongside HVAC mode — useful for underfloor heating projects
• Separate display page for each heating zone (e.g. zone A valve position, zone B status)
• Weekly scheduler built in: configure 4 setpoint periods per day in MDT Parametrizer
• CO2 sensor display: supports linking to external CO2 sensor GA (DPT 9.008, ppm)
• MDT Parametrizer generates the ETS6-compatible .knxprod file for download

Jung F50 EUI — ultra-flat room controller

The Jung F50 EUI is a 5mm-deep ultra-flat room controller designed for minimalist architectural interiors — hotels, serviced apartments and high-end residential. It displays room temperature and allows setpoint adjustment via capacitive push buttons. It is deliberately simpler than the Gira 2096 — no scene buttons, no lighting control pages.

Specification and function

• Depth: 5mm flush mount — virtually flush with wall surface
• Display: small e-ink or LCD showing actual temperature only
• Input: capacitive +/- buttons for setpoint adjustment
• Bus: KNX TP bus-powered
• Internal temperature sensor — same accuracy as Gira 2096
• ETS6 configuration: sends setpoint GA on button press, displays actual temp GA

When to specify the F50 EUI

• Hotel guest rooms — minimal control, maximum aesthetic
• Meeting rooms where lighting is controlled centrally (BMS)
• Bedrooms where a large touchscreen is unwanted
• Architects who specify flush-to-wall interfaces only
• NOT suitable where users need scene selection or lighting dimming at the thermostat

Zennio fan coil controller — a different category

The Zennio KLIC-DD is frequently mentioned alongside room controllers but serves a fundamentally different purpose. It is not a room display — it is a KNX fan coil unit controller that interfaces with 2-pipe and 4-pipe fan coil units via 0-10V and relay outputs. Understanding this distinction prevents misspecification.

Zennio KLIC-DD — what it actually does

• KNX fan coil unit (FCU) controller — DIN-rail mounted in the panel
• Fan: 3-speed relay outputs (low/medium/high) via DPT 5.001
• Heating coil valve: 0-10V analogue output (DPT 5.001 mapped to 0–10V)
• Cooling coil valve: 0-10V analogue output
• Internal PI thermostat: receives setpoint and actual temp from KNX GAs
• Typically paired with a separate room display (Zennio QUAD KNX)

Zennio QUAD KNX — the room display companion

• 4.3-inch colour touch display — the room-facing device
• Shows: actual temp, setpoint, fan speed, HVAC mode
• Sends setpoint to KLIC-DD via KNX group address
• Also controls: lights (4 channels), blinds, scenes
• Bus-powered — KNX TP
• Common in hospitality: QUAD display on wall, KLIC-DD in panel controlling the FCU

ETS6 PI thermostat parameters — room controller or thermostat

When the room controller or thermostat includes an internal PI (proportional-integral) controller, the ETS6 parameters directly affect heating and cooling comfort and energy efficiency. These parameters must be set correctly — defaults are rarely optimal.

PI controller ETS6 parameters — typical residential values

Proportional band (P-band):
  Typical value: 5K (5°C)
  Meaning: at 5°C below setpoint → 100% heating output
           at 2.5°C below setpoint → 50% heating output
  Too narrow (1K): frequent on/off cycling of valve
  Too wide (10K): slow response, permanent partial opening

Integral time (I-time):
  Typical value: 150 minutes
  Meaning: if steady-state error remains, output increases
           by P-band/100% every I-time minutes
  Too short (30 min): overshoot and oscillation
  Too long (300 min): slow correction of steady-state error

Cycle time (for switching outputs — radiator valves):
  Typical value: 15 minutes for radiator valve actuators
  Shorter cycle = finer control but more actuator wear
  For floor heating: 30 minutes (slow thermal mass)

Output group address:
  DPT 5.001 (0–255 → 0–100%) for continuous valve position
  DPT 1.001 (PWM on/off) for switching actuators

Dead band:
  Typical value: 0.5K — no output change within ±0.5K of setpoint
  Prevents hunting around setpoint in stable conditions

Floor heating vs radiator timing: Floor heating systems have high thermal inertia — the concrete slab takes 2–4 hours to respond to valve changes. Set I-time to 180–240 minutes and cycle time to 30 minutes for underfloor heating. For radiators with fast response, use 15-minute cycle time and 120-minute I-time. Never use the same parameters for both in the same project.

Room controller placement — rules for accurate temperature

The internal temperature sensor in a room controller reads the ambient air temperature at the device location. Poor placement produces permanently inaccurate readings that the PI controller cannot compensate for — resulting in uncomfortable rooms or wasted energy.

Placement rules

Height: 1.4m from finished floor — eye level for a seated or standing occupant. This is the optimal compromise for thermal stratification.
Wall selection: interior wall on the most-trafficked side of the room. Never on an exterior wall (cold in winter, hot in summer).
Distance from window: minimum 500mm from any window frame — solar radiation through glass causes false high readings.
Distance from door: minimum 300mm from door frame — door draughts cause false low readings.

Avoid these locations

Behind curtains or furniture: stagnant air pocket — reads 2–5°C higher than room average.
Corner of the room: poor air circulation — inaccurate by 1–3°C.
Above heat sources: radiators, underfloor heating manifold, electrical panels — sensor heats above room air temperature.
Direct sunlight: solar gain on the device casing heats the internal sensor even without convective air movement.
Near air supply grilles: supply air temperature ≠ room temperature — particularly in VAV systems.

Temperature offset correction in ETS6

If placement is non-ideal, apply a temperature offset correction:

ETS6 parameter: "Temperature offset" (most room controllers)
  Range: typically -3.0K to +3.0K in 0.1K steps

Calibration procedure:
  1. Let the room reach thermal equilibrium (2+ hours after HVAC idle)
  2. Measure actual air temperature with calibrated reference sensor
     at the same height as the room controller
  3. Note the difference: actual - displayed = offset to apply
  4. Enter offset in ETS6 and download to device

Example: displayed 23.4°C, reference reads 22.1°C
  → apply offset: -1.3K
  → device now reports 22.1°C

Recheck after changing room layout, adding insulation,
or replacing nearby heat sources.

Product comparison summary

Model	Display	HVAC	Lighting	Best for
Gira 2096 Touch	3.1" colour touch	Temp + setpoint + mode	4 channels + scenes	Residential — full control per room
MDT BE-GT55	5.5" colour touch	Temp + setpoint + mode + FCU zones	4 channels + scenes	Residential with floor heating zone display
Jung F50 EUI	Small LCD (temp only)	Temp + setpoint +/-	None	Hotels, minimalist bedrooms
Zennio QUAD KNX	4.3" colour touch	Temp + setpoint + fan speed	4 channels + scenes	Fan coil unit projects (paired with KLIC-DD)
Zennio KLIC-DD	None — DIN rail	PI controller + 3-speed fan + 0-10V valve	None	FCU control in panel — NOT a room display

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Home Assistant as KNX Visualisation: Dashboards, Voice and Mobile

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Floor Heating, Fan Coil and Heat Pump KNX Integration

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